Hi, Need help please, I’m trying to wire in a second zone using circulating pumps .
I have a Utica model MGB-100J forced hot water boiler.
There’s a “Honeywell Integrated high limit electronic ignition control #240008781” on the boiler with one zone wired in working great.
I believe I need to wire in a switching relay to control another zone.
I'm thinking a Taco SR501 or a SR503, but don’t know how to wire it to the current Honeywell control on the boiler?
Link to installation manual of my boiler here:
http://www.ecrinternational.com/secu...ument/3625.pdf
Link to sr501 instruction sheet here:
http://www.taco-hvac.com/uploads/Fil...ry/102-375.pdf
Link to sr503 instruction sheet here:
https://www.taco-hvac.com/uploads/Fi...ry/102-167.pdf
Thank you for looking and hopefully somebody can help me.

 

You will need to use the SR-503.

Remove the existing circulator from the boiler control along with the thermostat wiring.

Install the 503 and wire the existing thermostat and circulator to one of the 'channels' in the 503.

Connect the new thermostat and pump to another of the 503 channels.

Connect the ENDSWITCH from the 503 to the thermostat input of the boiler.

The circulator output of the boiler control will not be used.

 

Wow, Totally understand. You explained so simply.
I been racking my brain on how to do it with a 501 or a 503.
Thank you so much for your help and the fast responds .
I will post my results when I get around to finishing the job in a few day’s
Thank you again NJT.

 

Glad to help!

Yes, please do stop back and let us know how you made out.

 

Just out of curiosity!
It's cheaper and don't think I would go this route but would using 2 501's work. 1st floor pump + TT to 501 and 2nd floor pump +TT to the other 501 with both 6+5 terminals on 501's going to TT on the honeywell?

The 503 is just a little more money but would make for a much neater and easier job.

 

Yes, basically the same thing.............

But a bit more wiring on the AC side. No big deal I guess if you wanna save a few bucks.

 

Not worth the $23.20 savings, plus I could add another zone later if need be.
Thanks again

 

S,
You can use the 501. I believe you only need one.
Leave the initial wiring as is, that is leave your current pump on C1&C2 and just use the 501 to add the other pump.
This is what was done all the time until Taco came out with the multiple units.
The Honeywell R845A was the one we used back then and it does the same thing, but the Taco looks like it's cheaper.
Bring power in to terminals #1&2, jumper #1 to #3, pump goes to #4N/O &#2. #5&#6 go to TT on boiler.
TT from tstat obviously goes to TT on 501.
I believe this will work.

 

But Spott, how then will the original zone NOT get heat when the second zone is called?

Trigger relay for new zone, and BOTH pumps will run.

You need two relays, whether in one chassis, like the 503, or using two 501's.

 

I had originally hoped and felt the same way spott explained, but looked a little closer and looks like when the TT on the 501 calls both circulators will run.

 

There is a way to do a single zone add-on with one of the style aquastats that has the ZC and ZR terminals. I think that's what Spott is thinking of.

Your system with the integrated control that it has makes this not possible, thus the need to move the circ off the control.

 

Guys,
Sorry for the misinformation.
I did miss the part of the control you are using. I was thinking of the ZC,ZR terminals.
Trooper is right, you do need a relay for both or a multi zone relay.